AVB installed incorrectly, We did a nice replacement with a PVB in a tight spot!
An Atmospheric Vacuum Breaker cannot have constant pressure on it. It is not supposed to have pressure on it for more than 12 hours In a 24 hour period of time. It is not supposed to have any valves down stream. It is required to be 6″ above all piping and sprinkler heads to prevent any Back Pressure.
We corrected a wall of shame photo.